Nutritional Studies on Dried Functional Food Ingredients Containing omega-3 Polyunsaturated Fatty-Acids.

Abstract

The nutritional benefits of fish oils are generally attributed to their content of long chain omega-3 polyunsaturated fatty acids (PUFAs). Diets rich in these fatty acids are known to reduce the risk of coronary thrombosis, and are recommended to those who are susceptible to atherosclerosis. In addition, some of these long chain PUFAs play an important role in early infant nutrition, in the development of vital human organs such as the neural tube. However, practical difficulties arise in achieving an adequate daily intake of fish oils to obtain these physiological benefits. Per capita fish consumption is low in many countries, especially of oily fish with high levels of omega-3 PUFAs. Fish oil, while available as a dietary supplement, is not universally appealing in that form. Attempts to incorporate fish oil into food formulations have had limited success mainly because of fishy flavours coming through in the consumer products. Fish oil is particularly susceptible to oxidation, which results in fishy, painty and metallic flavours. Hence the main aim of this study was the development of a dried ingredient in which the formulation and related processing conditions were optimised to protect the fish oil from oxidation. Protection of any sensitive oil may be achieved by means of microencapsulation, whereby oil is dispersed as very fine droplets in emulsions. During subsequent spray drying the droplets are effectively sealed inside a protective coating of protein surrounded by carbohydrate. The objective was, therefore, to evaluate microencapsulation as a means of extending the shelf-life of fish oil in powder form thus increasing its versatility as a nutritional ingredient in food formulations.